Re: If not doing something because it was "inconvenient" was the ciriteria for Brexit..
On Brexit day the UK can decommission their Galileo ground stations in UK territories unilaterally, after all if the EU doesn't want us to be a part of it, then we withdraw. And since we have put a lot of money into it and now they won't let us use it, a full refund (with interest) would be well in order.
And the EU can set up new ground stations relatively easily - they will be happy and eager to get a greater share of the work. There will be no full refund because the contractors will be paid for the work done, according to the contracts signed.